Thermodynamic simulation of metal-thermal boron reducing

Abstract

. To improve the quality of steel and cast iron, the micro-alloyed by boron is applied, which is introduced into the melt within a scope of complex ferroalloys. There is information about rather effective application of silicon and aluminum as reducing agents, introduced within a scope of complex ferroalloy with manganese, chrome, tungsten and molybdenum. However, no information was found about application of such a ferroalloy for reducing of boron. Therefore, the purpose of the study was the thermodynamic simulation of boron simultaneous reducing by silicon and aluminum from the CaO–SiO 2 –MgO–B 2 O 3 oxide system. The influ-ence of aluminum content within a complex reducing agent on the boron reducing degree from the oxide system of the following compositions %: 36,7 CaO; 5,6 SiO 2 ; 2,8 MgO; 54,9 B 2 О 3 was studied. For particular study, the alloys of the following composition were taken: %: 60 Si – 5 Al – 35 Fe; 55 Si – 10 Al – 35 Fe; 50 Si – 15 Al – 35 Fe and 65 Si – 35 Fe. The simulation was accom-plished within a package of applied programs HSC Chemistry 6.12 with application of Equilibrium Composition module within the temperature range 1400–1600 ° С with a step of 50 ° С . It was determined, that replace of silicon in the alloys by aluminum results in considerable growth of reducing degree, which can reach 99%. Alloys с [Al] orig = 0–52 % have the lowest reducing degree. Presence of с [Al] orig = 5 % in the original alloy enables to increase the reducing degree until 69%. The further growth of the original aluminum content until 10 and 15% enables to reach the reducing degree of 85 and 94%. Based on the study results the conclusion was made about preference to apply aluminum from the Fe–Si–Al complex ferroalloy for boron reducing from the oxide system, since the degree of boron reduction degree is much higher comparing with application only silicon at the same total reducing agent (Si + Al = 65 %) quantity.